1. Field
The present disclosure relates to a synergistic herbicidal composition containing mesotrione and halosulfuron-methyl, each in particular crystal modifications. The composition finds use in controlling the growth of undesirable plant, particularly in crops, including using the aforementioned composition.
2. Description of Related Art
The protection of crops from undesirable plant, which inhibits crop growth, is a constantly recurring problem in agriculture. To solve this problem, researchers are trying to produce an extensive variety of chemicals and chemical formulations effective in the control of such undesirable growth. Chemical herbicides of many types have been disclosed in the literature and a large number are in commercial use.
Some herbicidal active ingredients have been shown to be more effective when applied in combination rather than applied individually, this effect being referred to as “synergism.” According to Herbicide Handbook of the Weed Science Society of America, Seventh Edition, 1994, page 318, “synergism” is an interaction of two or more factors such that the effect when combined is greater than the predicted effect based on the response to each factor applied separately.
The compound 2-(4-mesyl-2-nitrobenzoyl)cyclohexane-1,3-dione has the common name mesotrione. Mesotrione is a substance that can form polymorph crystals. Two different forms, crystalline modifications I and II, of mesotrione are described in WO2006021743, which is incorporated herein by reference for all purposes. Mesotrione is active as a herbicide and is now commercially available in a range of formulations for controlling the growth of undesirable plant.
The compound methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyrazole-4-carboxylate, having the common name halosulfuron-methyl, is a known herbicide.
Halosulfuron-methyl controls annual broad-leaved weeds and nutsedge species, in maize, sugarcane, rice, sorghum, nuts and turf. It can be manufactured by the process described in U.S. Pat. No. 4,668,277, which results in a compound that is present in an amorphous state which is highly viscous. Due to its viscosity, the amorphous state of halosulfuron-methyl has a poor spray equipment clean-out property and will heavily contaminate the spray equipment.